As little ones develop, they have periods of learning in certain areas then suddenly they go off in a different direction and the skill they just learned sometimes seems to go away. If you think about it like windows opening and closing in the brain it will help you. A window can open for running and kicking but close for brushing their own hair, it will seem like they just don't have any idea how anymore. The skill is still there, just not in use right then.
When a window is closed nothing gets in...in that area. The child brains is focused on something else. It may seem like you are banging your head on a wall with potty training but she is still learning.
When she is ready it will be like others have said, she'll just start going and be mostly done, maybe a few accidents.
Keep encouraging her but make it fun. When she sits on the potty you can give her a reward such as a tiny M&M, the ones for baking are tiny. Make it a positive experience. NO PUNISHMENT!! She will associate negative things with going. She can have a star chart for every time she sits, she could have a special snack each time she sits, or one reward for when she sits and another for actually going.
Don't stress out because you are only making it harder on yourself. When that window opens you will see the rewards of your work.